Mine safety-lamp.



Patented Nov. 3, 1914 2 SHEETS-SHEET l.

f z. JJ 4. 3

P. FARBBR.

MINE SAFETY LAMP.

APPLICATION FILED DEG. 2| 1913.

F.PRBER.

MINE SAFETY LAMP.

APPLICATION FILED DEC. 2. 1913.

Patented Nov. 3, 1914.

2 SHEETS-SHEET 2.

rnrrz FRBER, or DORTMUND, GERMANY.

C MINE SAFETY-LAMP.

Specicationof Letters Patent.

Patented Nov. 3, 1914.

Application led December 2, 1913. Serial No. 804,274.

To all whom it may concern Be it known that I, Fnrrz FRBER,\a sub-A ject of theKing of Prussia, German Emperor, and resident of Dortmund, in the Kingdom of Prussia, German Empire, have invented an Improved and Novel Mine Safety-Lamp, of which the following is a specificatie This invention relates to electric safety lamps intended especially for use in mines, particularly in such ones where fire damp and other explosive gases or gas mixtures are to be expected.` The lamp makes use of electricity as illuminative medium and has, besides, special means for indicating an accumulation of lire damp by means of a. flame. This special flame-formingpart of the lamp acts thus as a lire damp indicator, and as this indicator requires particularly careful protection it is arranged in the midst of a cavity of thecasing which incloses a nearly closed hollow cylindrical accumulator. Means are provided to let the indicating flame in question arise onlyif a search as to the presence of fire damp or the like is made, whereas if this is notl the case, the lire damp or other gas or gas mixture is prevented from getting access to the lamp part in quest-ion. The electric incandescent lamp is particularly protected by a strong glass hood, and an automatic cut-out is provided which breaks the circuit if this hood and the bulb should be broken, the manner of action being such that the circuit is shortcircuited whereby a fuse is caused to melt, breaking now the circuit and causing the lamp to be extinguished. Also this fuse is inclosed in such a manner that, the sparks arising on the fuse becoming active cannot possibly come in contact with the fire damp or the like. The construction of the lamp is such that the lament, as well as the fire damp indicator, are very securely protected,

'an ignition of the usually present explosive gases being prevented even if damage to the ing, however, broken and the re damp in'- dicator being in inoperative position; Fig. 3 is an exterior side view of the lamp; and Fig. 4 is a horizontal section o-n line A-B of Fig. 3. Fig. 5 is a detail view on an enlarged scale of the short circuiting device.

The casing of the lamp consists of two parts 1 and 2 which are connected by threads with each other. 1 is the main part of the casing, or the casing proper, whereas 2 forms a kind of hood. The part 1 is intended to receive the electric accumulator, as well as the fire damp indicator. The a/ccumulator 3 is made asa nearly vcompletely closed annular cylinder, the central space of which contains the lire damp indicator 4. In other words, the annular cylinder is not a complete cylinder, but a part of its circumference is wanting, as shown in Fig. 4. J ust where that part 1s wanting, there the casing l has a vertical series of horizontaL aper.

tures 5, Fig. 3, through which the central space vmentioned is open for inspection.

The upper part ofthe hood 2 of the casing takes over the flangeJ at the lower end of the protective glass hood of the incandescence lamp 7 The lamp is supplied with currentv romthe accumulator 3 irst by means of conduits 8 81 which terminate at yielding contacts 9 91. The hood 2 contains also a disk 10 of a non-conducting material which is pressed against said contacts when the parts 1 and 2'are screwed together. To the disk 10 are atlixedconducting plates 11 I2, the position of which with regard to the screw-threads of the parts l and 2 is such that said plates'are contacting with the pins 9 91 when the parts 1 and 2 are properly connected with each other. The screw 14 securing the conducting plate 11 to the disk 10 serves also for connecting this plate with another conducting plate 13 to which is attached a cap 15 forming a neck 151 serving as socket for the incandescence lamp.' The other pole of the accumulator is connected by the contact 91, the plate 12, the screw 16, and the metal band 17 with the central part of the disk 10, where there are, superposed small disks 19, 20, 21, which are secured to the end of the -metal band by means of a screw 18. The disk 19 consists of brass, the disk 2O of a non-conducting material, such as liber or the like, and the disk 21 consists also of such material but hasa metallic rim. The disk 20v has a central aperture 201 through which a fuse wire, the thickness( of which corresponds to the strength of the current, 1s passed, this wire connecting the plate 1.9

, with the metallic rim 211 of the disk 21.

The cap 15 forms a kind of reflector. The lamp 7 is held Vby the sleeve-like central part of the reflector, as well as by a helix 23 inserted between the bulb and the upper end mediation of which the current is conducted to the lamp-socket 27 and lamp proper, or the lamp filament respectively. 'Ihe current then flows back to the other pole of the accumulator through the reflector 15 and the other parts already described. The socket is somewhat longer than the neck or sleeve 151,

in consequence of which the contact plate 25 is prevented from touching the sleeve as long as the lamp is held depressed by the upper helix. If now either the protective hood 6,

or the lamp 7, is broken, the action of the helix 23 ceases and the helix 24 now forces the socket 27 upward, the disk 25 now coming in contact with the edge of the sleeve 151 and short-circuiting the circuit. 'Ihe fuse 22 now melts and the circuit is completely interrupted. It is obvious that fire damp or the like finding access into the broken lamp can not become ignited because I the lamp is extinguished before the explosive gas can enter the interior of the lamp. The parts in question are then in the position shown in Figi 2 where the fuse wire is represented as melted. This interruption takes place in the closed chamber formed by the aperture of the disk 20, to which the gases cannot find access.

The fire damp vindicator et has a receptacle 28 containing a fuel, such as petrol, alcohol, hydrogen, or the like. 29 is a wick which projectsalittle from a small tube 30. 31 is another small tube that is under the pressure of a spring 32V and projects in its turn a little over thewick. Noname can burn if the arts 1n question are in thisposition. The tu 31 isl rigidly connected with a bolt 34 by means of a bridge' 33, and the bolt has a head 35 situated below the bottom ofthe casing 1.

Therefore, when drawing the bolt 34 downwardfthe tube 31 also is drawn downward r and the Wick is freed at the same time, when drawing the knob' downward, contact is established between the spring 36 and a bolt 87 aiiixed to the bridge 33 the current of the accumulator finding now a way from the central screw 18, the elastic contact piece 38,

and the wire 39, to the bolt 37 and further to a heating spiral 40 consisting of platinum or the like. This spiral is situated just over the wick and is thus in a position to ignite the same, after which the examination or search as to the pressure of fire damp may commence.

The arrangement in question may be appropriately modified in this way that the wick is freed by a rotary movement of the bolt 34, and a suitably disposed spring which has been put under tension during that movement turns thebolt back into its former posit-ion extinguishing thereby the burning wick. The lire damp indicator can thus remain active only as long as the bolt is held fast after the irst movement, whereas when the bolt is let loose it returns at once automaticallyinto its former position.

Air is admitted to the indicator through the apertures 41 in the bottom and in the upper part' of the lamp, also through the s lots 5. These slots serve also for making visible the changes produced in the flame by the presence of lire damp, viz. the elongation of the iame cone, or aureole respectively. rlne wire cylinder 42 prevents the flame from getting to the outside.

Instead of the tire damp indicator just described, also another kind of indicating device may be arranged in the space provided for the reception of such device. The section of this space need not be indispensably circular, out may have oval or hexagonal or any other suitable shape:

Having no w described my invention, what I desire to secure by a patent of the United States is:

1. In an electric safety lamp of the kind described, the combination, with a reector; having a sleeve-forming neck; an incandescence lamp inserted with its socket into said sleeve so as tobe in electric contact with the same; means for depressing said socket within said sleeve, and an elastic contact as counterpart for the socket-contact, said elastic contact being formed by a plate so arranged as to be adapted to short-circuit the lamp by contacting with said sleeveforming neck, if the bulbV of the lamp breaks. l

2. In an electric safety lamp of the kind described, the combination with a reflector having a sleeve-forming neck, an incandescence lamp'inserted with its socket into said sleeve so as tov be in electric contact with the same and Vto be adapted to be longitudinally displaced in it, a conducting counter pressure spring with a disk at the socket contact of the lamp, a plate of 4non-:conducting material with a closed bore, a metal plate carrying said last named plate, a plate of non-conducting material'having a metal rim carried by sald plate of non-conducting material, a safety fuse arranged in said bore, connecting said4 metal plate with the metallic rim of said plate of non-conducting material, said sprmg adapted upon breakage of the lamp bulb to press said disk against the reflector neck thereby short-circuiting the lamp and causing the fuse' to melt.

3. `In an electric safety lamp of the kind described, the combination, with an incandescence lamp; conductors for connecting it with a source of current; an accumulator providing said source arranged in a nearly closed annular vessel having a central space adapted to receive a fire-damp indicator or the like.

4. In an electric safety lamp of the kind y described', the combination, with an incandescence lamp; conductors for connecting it with a source of current; an accumulator providing said source arranged in. a nearly closed annular vessel having a central space;

- a' fire-damp indicator in said space; ,said

indicator consisting of a fuel vessel, a Wick tube, a Wick slightly projecting above the Wick tube end, another tube carrying an ignition device around said Wick tube adapted to be moved With respect to said Wick tube from the outside by means of a bolt, a spring adapted to return said other tube ta its former position, substantially and for the purpose as described.

5. In an electric safety lamp of the kind described, the combination.` with an incandescence lamp; conductors for connecting it With a source of current; an accumulator providing said source arranged in a nearly providing said source arranged in a nearly closed annular vessel having a central space; a fire-damp indicator in said space; said indicator consisting of a fuel vessel, a Wick 'with a source of current; an accumulator tube, a Wick slightly projecting above the Wick tube end, another tube around said Wick tube adapted to be moved With respect to said Wick tube from the outside by means of a bolt; a contact-plate supplied With current from the accumulator; a contact bolt aiiixed to said movable tube by means of a bridge; and a heating spiral attached to said bolt and extending over the wick, substantially and for the purpose as described. In testimony whereof I aiiX my signature in'presence of tWo Witnesses.

FRITZ FARBER. Ins] Witnesses: ALBERT NUFER, i

. FRANCES NUFER. 

